Franck-Condon simulation of the anion photoelectron spectroscopy of CrO2 by coherent state method

The equilibrium geometries and harmonic vibrational frequencies of CrO2(X3B1) and CrO2-(X4B1) were calculated using density functional theory and couple cluster method with various basis sets. A program was developed to calculate multidimensional Franck-Condon factors based on coherent state method. Its application to the photoelectron spectroscopy of the CrO2(X3B1)←CrO2-(X4B1) photodetachment process was presented. The simulation at the CCSD(T)/aug-cc-pwCVTZ level of theory is in good agreement with the experimental spectroscopy, revealing that the hot bands contribute to the spectroscopy remarkably. All peaks of the experimental spectroscopy were assigned explicitly according to the theoretical modeling. Our calculations support original experimental assignments. In addition, the agreement between the calculated and experimental adiabatic electron affinities of CrO2(X3B1) is excellent.